One type of elastic shaft coupling has, between a driving and a driven coupling half or coupling member, a substantially ring-shaped or annular coupling element composed of elastic material, usually an elastomer and especially rubber, whereby, for connection of that coupling element or body with the coupling halves or the driving and driven members of the coupling which are connected to the respective shafts, metallic members are embedded in, connected by vulcanization to, or otherwise form parts of the elastic body.
These metal members are provided with bores traversed by fastening screws which can be threaded into the respective coupling halves or connected thereto by bolt and nut connections.
The coupling elements or bodies itself can be split in the region of one of the metal parts and through the segments formed by the split metal parts. Fastening screws and at least one fixing device held by the fastening screw can retain the coupling closed at the split.
An elastic shaft coupling of this type is known from the catalog entitled “KOP-FLEX ELASTOMERIC™ Couplings”, page 96 of the firm KOP-FLEX INC., Harmans Road, Harmans, Md. 21077. This elastic coupling comprised basically of a polygonal annular body of rubber into which at uniformly spaced or equispaced relationship metal parts or so-called inserts have been vulcanized. These metal parts are extended in the axial direction of the coupling beyond the annular body and thereby form axial projections extending alternately in one and the other axial direction and parallel to the longitudinal or rotation axis of the coupling system. The metal parts have a generally wedge shape, i.e. a cross section which tapers toward the axis of rotation and engage in matching wedge-shaped grooves in the peripheries of two hubs which form the coupling together with that elastic body. The hubs are the driven and driving members of the coupling. Each of the metal parts, of which one is split into two segments, has a radially extending stepped bore to receive a respective fastening screw which is threaded into the respective hub. The underside of the head of the screw then presses against the step of the stepped bore so that each metal part is drawn into or pressed into the respective wedge-shaped groove of the respective hub. The wedge and groove arrangement form together with the respective fastening screw a fixing device which, in the case of the segmented metal part holds the two segments securely together and the ring closed. To open the ring, the system must be disassembled and such openings and disassembly is not possible without enabling the assembly to shift or move in the axial direction. An axial movement is necessary as well for reassembly or mounting.
This advantage of the prior art coupling can be obtained only with relatively high cost and the need to provide at each side of the coupling a respective hub as the connector for the coupling ring.
DE 2 019 608 C describes an elastic shaft coupling of which a million have been marketed and which also provides a polygonal annular body of elastic material, like rubber, in which metal bodies have been vulcanized at uniformly-spaced intervals. These metal bodies are alternately of different configuration so that the bores for the screws which traverse them are alternately oriented in the axial and the radial direction. In this manner it is possible to have the axially oriented fastening screws threaded into a planar surface such as that of a flange constituting or forming part of one coupling half. The radially oriented fastening screws can be threaded into a cylindrical outer surface of the other coupling half. This construction provides the advantages of the arrangement previously described and in addition an advantage in that it allows the coupling halves to be free from any special feature. Other than the threaded bores for receiving the fastening screws, the system can be provided between a flanged member and one having a cylindrical attachment surface. In this arrangement as well, however, it is not possible to mount or dismount the coupling ring without shifting the system to a certain extent in the axial direction.